Twist Drill Bit
Twist bits are one of the most popular kinds of drill bits and are often used for non-specialized, general-purpose drilling tasks. Although there are several distinct twist drill bit subtypes, all twist bits have a similar basic construction. The primary feature that distinguishes a twist bit is its form; these bits are easily recognised by their well-known helix or spiralled fluted profiles. Even though there are several types of twist drill bits designed for use with various materials and certain purposes, all of them have a few essential characteristics. Twist drill bits include a shank at one end and a cutting tip at the other in addition to spiral flutes around a cylindrical shaft.
Types of Twist Drill Bits
Twist drill bits come in a variety of varieties, each designed for use with certain materials or in particular specialised applications. We’ll look at some of the most well-liked and generally accessible variations on the traditional twist drill bit design in the sections that follow.
Long Twist Drill Bits
In order to drill holes that are deeper than those made by a standard-length drill bit, long twist drill bits are used. A common illustration would be drilling through the ends of the workpiece to a depth of up to one foot in order to place security latches on a door.
To do daily activities like these, a very long twist drill bit would be needed, but its primary potential drawback is that it may have a tendency to wander more. In addition, longer twist bits are more likely to shatter at lower gauges than shorter bits, especially when more effort is needed to penetrate deeper layers of material. Short-form twist drill bits are also offered.
Reverse Twist Drill Bits
Drill bits with a reverse twist are designed to operate with drill sets that rotate in the other direction (counter-clockwise). Reverse twist drill bits, on the other hand, are manufactured with their fluted cutting surfaces facing the other way, as opposed to regular drill bits, which would simply drag their cutting edge backwards through the inside of the hole with the drill operating backwards. The reverse drill bit produces the same kind of cutting action as a conventional drill bit when moving clockwise when it is put into a chuck and the drill is operated counter clock wise. When the slots on a screw head have worn out, this technique for extracting screws may be quite helpful.
High Speed Twist Drill Bits
Most twist drill bits are made of high-grade steel, primarily of two specific formulations that are particularly prevalent for particular scenarios:
High-Speed Steel (HSS)
- High-speed twist bits are essentially an all-purpose form of drill bit, and the majority of HSS twist bit varieties are appropriate for use in routine drilling operations.
- Since HSS twist bits are designed to endure the greater temperatures produced by the increased friction required in drilling metal without losing hardness, they are necessary for drilling through many types of metallic workpieces and surfaces (temper)
- On the other hand, if all you want to do is drill into wood, you may use a carbon steel twist drill bit.
- Although drilling most kinds of wood and composite lumber materials is unlikely to result in this problem, carbon steel twist bits have a tendency to be less flexible and more susceptible to shatter under greater torque pressures and temperatures than HSS variants.
- Although more fragile and less durable than HSS bits, particularly at higher operating temperatures, carbon steel twist drill bits may prove to be a more affordable alternative for drilling tasks that only involve wood.
Twist Drill Bits for Metals
You cannot normally expect to use a conventional steel or carbon steel drill bit intended for cutting through wood if you need to drill through metal. This is particularly evident when working with objects that have very abrasive surfaces, like steel. However, there is a decent selection of metal-specific treated, coated, and tipped twist drill bits that are all designed to provide a more durable cutting tool for taking on those more difficult metalworking tasks. Cobalt drill bits and titanium twist drill bits are the most readily accessible. These are made specifically to drill through metals, much as standard high-speed steel (HSS) drill bits. The main distinction between cobalt steel twist drill bits and titanium drill bits is that the latter are made completely of solid cobalt steel, while the former are toughened with a titanium oxide (or titanium nitride, often known as TiN drill bits) coating. Due to the production method, drill bits of this kind cannot be sharpened if they get dull over time from usage on sheet metals, despite the titanium versions being tougher due to their oxide coating. On the other hand, because cobalt steel twist drill bits are produced from a single piece, they may be sharpened. They are also quite abrasive and work especially well for drilling through tough materials like stainless steel, cast iron, and titanium. Cobalt steel may also be replaced with carbide and carbide-tipped twist drill bits, which enable very fast cutting rates and provide longer tool life. When making a purchase, you must consider which cutting tool is ideal for your degree of skill, the materials you will be dealing with, and the lifetime you need since increasing hardness often results in a more brittle product.
Twist Drill Bit Sizes
The bit sizes listed in the manufacturer specifications for twist drill bits always include both the length and the diameter of the drill bit body. The largest twist drill bit that you will often find in drill bit sets will probably be between 25 and 30 mm in size for the majority of usage. However, it is often far more usual to utilise a variety of smaller and shorter twist drill bits for many common applications, unless you are doing a very heavy-duty project. Furthermore, it’s important to keep in mind that bit sizes may be expressed in imperial or metric measures, and the most of twist drill bit sets will come with a decent selection of sizes to handle the bulk of daily tasks. The majority of the time, tiny twist drill bits are beneficial for precise drilling tasks or for installing smaller, more complex fixtures, fasteners, and hardware. Additionally, you need to be aware of the minimum twist drill bit shank size needed for the drill you’ll be utilising at work. The majority of cordless drills, in general, have a top chuck size of 10mm, however larger, more powerful drills may often allow greater shank sizes for employing larger, longer bits. Therefore, it is advised to use a drill with a bigger chuck to accept twist drill bits with thicker shanks if you need to drill deep or wide-bore holes. As an alternative, purchasing a set of twist drill bits will provide you access to a variety of bits in various sizes that are perfect for carrying out several jobs in various situations.